Add support for RTSP Mp4a-Latm

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/RtspMediaTrack.java

@@ -55,6 +55,7 @@
   private static final String PARAMETER_H265_SPROP_VPS = "sprop-vps";
   private static final String PARAMETER_H265_SPROP_MAX_DON_DIFF = "sprop-max-don-diff";
   private static final String PARAMETER_MP4V_CONFIG = "config";
+  private static final String PARAMETER_MP4A_CPRESENT = "cpresent";
 
   /** Prefix for the RFC6381 codecs string for AAC formats. */
   private static final String AAC_CODECS_PREFIX = "mp4a.40.";
@@ -211,11 +212,18 @@ public int hashCode() {
         checkArgument(channelCount != C.INDEX_UNSET);
         checkArgument(!fmtpParameters.isEmpty());
         if(mediaEncoding.equals(RtpPayloadFormat.RTP_MEDIA_MPEG4_AUDIO)) {
-          Pair cfgOpts = getSampleRateAndChannelCountFromAudioConfig(
-              fmtpParameters, channelCount, clockRate);
-          channelCount = cfgOpts.first;
-          clockRate = cfgOpts.second;
-          formatBuilder.setSampleRate(clockRate).setChannelCount(channelCount);
+          boolean isCPresent = true;
+          if (fmtpParameters.get(PARAMETER_MP4A_CPRESENT) != null && fmtpParameters.get(
+              PARAMETER_MP4A_CPRESENT).equals("0")) {
+            isCPresent = false;
+          }
+          @Nullable String configInput = fmtpParameters.get(PARAMETER_MP4V_CONFIG);
+          if (!isCPresent && configInput != null && configInput.length() % 2 == 0) {
+            Pair configParameters = getSampleRateAndChannelCount(configInput);
+            channelCount = configParameters.first;
+            clockRate = configParameters.second;
+            formatBuilder.setSampleRate(clockRate).setChannelCount(channelCount);
+          }
         }
         processAacFmtpAttribute(formatBuilder, fmtpParameters, channelCount, clockRate);
         break;
@@ -311,33 +319,30 @@ private static void processAacFmtpAttribute(
   }
 
   /**
-   * Parses an MPEG-4 Audio Stream Mux configuration, as defined in ISO/IEC14496-3. FMTP attribute
-   * contains config which is a byte array containing the MPEG-4 Audio Stream Mux configuration to
-   * parse.
+   * Returns a {@link Pair} of sample rate and channel count, by parsing the
+   *  MPEG4 Audio Stream Mux configuration.
+   *
+   * fmtp attribute {@code config} includes the MPEG4 Audio Stream Mux
+   * configuration (ISO/IEC14496-3, Chapter 1.7.3).
    */
-  private static Pair getSampleRateAndChannelCountFromAudioConfig(
-      ImmutableMap fmtpAttributes,
-      int channelCount,
-      int sampleRate) {
-    @Nullable String configInput = fmtpAttributes.get(PARAMETER_MP4V_CONFIG);
-    if (configInput != null && configInput.length() % 2 == 0) {
-      byte[] configBuffer = Util.getBytesFromHexString(configInput);
-      ParsableBitArray scratchBits = new ParsableBitArray(configBuffer);
-      int audioMuxVersion = scratchBits.readBits(1);
-      if (audioMuxVersion == 0) {
-        checkArgument(scratchBits.readBits(1) == 1, "Invalid allStreamsSameTimeFraming.");
-        scratchBits.readBits(6);
-        checkArgument(scratchBits.readBits(4) == 0, "Invalid numProgram.");
-        checkArgument(scratchBits.readBits(3) == 0, "Invalid numLayer.");
-        AacUtil.Config aacConfig = null;
-        try {
-          aacConfig = AacUtil.parseAudioSpecificConfig(scratchBits, false);
-        } catch (ParserException e) {
-          throw new IllegalArgumentException(e);
-        }
-        sampleRate = aacConfig.sampleRateHz;
-        channelCount = aacConfig.channelCount;
+  private static Pair getSampleRateAndChannelCount(String configInput) {
+    int channelCount = 0, sampleRate = 0;
+    byte[] configBuffer = Util.getBytesFromHexString(configInput);
+    ParsableBitArray scratchBits = new ParsableBitArray(configBuffer);
+    int audioMuxVersion = scratchBits.readBits(1);
+    if (audioMuxVersion == 0) {
+      checkArgument(scratchBits.readBits(1) == 1, "Invalid allStreamsSameTimeFraming.");
+      scratchBits.readBits(6);
+      checkArgument(scratchBits.readBits(4) == 0, "Invalid numProgram.");
+      checkArgument(scratchBits.readBits(3) == 0, "Invalid numLayer.");
+      @Nullable AacUtil.Config aacConfig = null;
+      try {
+        aacConfig = AacUtil.parseAudioSpecificConfig(scratchBits, false);
+      } catch (ParserException e) {
+        throw new IllegalArgumentException(e);
       }
+      sampleRate = aacConfig.sampleRateHz;
+      channelCount = aacConfig.channelCount;
     }
     return Pair.create(channelCount, sampleRate);
   }

libraries/exoplayer_rtsp/src/main/java/androidx/media3/exoplayer/rtsp/reader/RtpMp4aReader.java

@@ -54,7 +54,7 @@
   private int fragmentedSampleSizeBytes;
   private long startTimeOffsetUs;
   private long sampleTimeUsOfFragmentedSample;
-  private int numSubFrames;
+  private int numberOfSubframes;
 
   /** Creates an instance. */
   public RtpMp4aReader(RtpPayloadFormat payloadFormat) {
@@ -78,9 +78,9 @@ public void onReceivingFirstPacket(long timestamp, int sequenceNumber) {
     checkState(firstReceivedTimestamp == C.TIME_UNSET);
     firstReceivedTimestamp = timestamp;
     try {
-      numSubFrames = getNumOfSubframesFromMpeg4AudioConfig(payloadFormat.fmtpParameters);
+      numberOfSubframes = getNumOfSubframesFromMpeg4AudioConfig(payloadFormat.fmtpParameters);
     } catch (ParserException e) {
-      e.printStackTrace();
+      throw new IllegalArgumentException(e);
     }
 }
 
@@ -94,23 +94,30 @@ public void consume(
     if(fragmentedSampleSizeBytes > 0 && expectedSequenceNumber < sequenceNumber) {
       outputSampleMetadataForFragmentedPackets();
     }
-    int sampleOffset = 0;
-    for (int subFrame = 0; subFrame <= numSubFrames; subFrame++) {
+    int audioPayloadOffset = 0;
+    for (int subFrame = 0; subFrame < numberOfSubframes; subFrame++) {
       int sampleLength = 0;
 
-      /* Each subframe starts with a variable length encoding */
-      for (; sampleOffset < data.bytesLeft(); sampleOffset++) {
-        sampleLength += data.getData()[sampleOffset] & 0xff;
-        if ((data.getData()[sampleOffset] & 0xff) != 0xff) {
+      /**
+       * This implements PayloadLengthInfo() in Chapter 1.7.3.1, it's only support one program and
+       * one layer.
+       * Each subframe starts with a variable length encoding.
+       */
+      for (; audioPayloadOffset < data.bytesLeft(); audioPayloadOffset++) {
+        int payloadMuxLength = data.peekUnsignedByte();
+        sampleLength += payloadMuxLength;
+        if (payloadMuxLength != 0xff) {
           break;
+        } else {
+          data.setPosition(audioPayloadOffset + 1);
         }
       }
-      sampleOffset++;
-      data.setPosition(sampleOffset);
+      audioPayloadOffset++;
+      data.setPosition(audioPayloadOffset);
 
-      // Write the audio sample
+      /* Write the audio sample */
       trackOutput.sampleData(data, sampleLength);
-      sampleOffset += sampleLength;
+      audioPayloadOffset+= sampleLength;
       fragmentedSampleSizeBytes += sampleLength;
     }
     sampleTimeUsOfFragmentedSample = toSampleTimeUs(startTimeOffsetUs, timestamp,
@@ -140,25 +147,25 @@ public void seek(long nextRtpTimestamp, long timeUs) {
    * @throws ParserException If the MPEG-4 Audio Stream Mux configuration cannot be parsed due to
    *     unsupported audioMuxVersion.
    */
-  private static Integer getNumOfSubframesFromMpeg4AudioConfig(
+  private static int getNumOfSubframesFromMpeg4AudioConfig(
       ImmutableMap fmtpAttributes) throws ParserException {
     @Nullable String configInput = fmtpAttributes.get(PARAMETER_MP4A_CONFIG);
-    int numSubFrames = 0;
+    int numberOfSubframes = 0;
     if (configInput != null && configInput.length() % 2 == 0) {
       byte[] configBuffer = Util.getBytesFromHexString(configInput);
       ParsableBitArray scratchBits = new ParsableBitArray(configBuffer);
       int audioMuxVersion = scratchBits.readBits(1);
       if (audioMuxVersion == 0) {
         checkArgument(scratchBits.readBits(1) == 1, "Invalid allStreamsSameTimeFraming.");
-        numSubFrames = scratchBits.readBits(6);
+        numberOfSubframes = scratchBits.readBits(6);
         checkArgument(scratchBits.readBits(4) == 0, "Invalid numProgram.");
         checkArgument(scratchBits.readBits(3) == 0, "Invalid numLayer.");
       } else {
         throw ParserException.createForMalformedDataOfUnknownType(
             "unsupported audio mux version: " + audioMuxVersion, null);
       }
     }
-    return numSubFrames;
+    return numberOfSubframes + 1;
   }
 
   /**